This invention generally relates to oils or oil additives exhibiting extreme pressure properties, and more particularly to a sulfur-chlorinated product containing in major proportions cyclic oils and fat products.
In U.S. Patent application, Ser. No. 395,741, filed September 10, 1973 (now U.S. Pat. No. 3,847,827) entitled "Cyclic Sulfur-Chlorinated Oil and Process of Making" and assigned to the same assignee as the present invention, and herein incorporated by reference, disclosed was a process of making sulfurchlorinated cyclic oils having anti-weld properties. Briefly, it was discovered that cyclic oils, which are generally by-products of an oil refining process and which contains substantial amounts of polynuclear aromatic compounds boiling between 350.degree. and 800.degree.F, if reacted with an amount of sulfuric acid less than the maximum amount required to react completely with the oil, but a sufficient amount to precipitate unwanted impurities, and thereafter was sulfur-halogenated by directly reacting it with a sulfur halide, after removal of any resulting sludge and hydrogen halide, a stable and homogeneous oil exhibiting anti-weld and some extreme pressure properties could be obtained.
The use of various fatty substances to enhance the extreme pressure properties of an oil is known, including the use of sulfur-chlorinated fats to this end. The ability of certain fats, especially sulfur-chlorinated fats to enhance the extreme pressure properties of a lubricating oil, is thought to be due, in part, to the extremely good wetting properties of such fatty substances. See, for example, U.S. Pat. No. 2,694,046 which discloses sulfur-chlorinated fatty materials such as oleic acids, lard oil, and the methyl esters of lard oil.
However, in recent years, the cost of such fatty oils has risen considerably, paralleling the cost of food, since most of these derivatives are obtained from animal fats. These fats, however, find large volume use as a raw material for glycerine which, after glycerine extraction, yields waste products comprising large amounts of fatty acids. These glycerine extracted products are generally obtained by acidulation with an acid such as hydrochloric acid, and are usually known as acidulated foots. Such foots may be obtained from both vegetable and animal sources, as for example, cotton seed foots, soy foots, coconut foods, etc. To date, such acidulated foots have had little or no commercial value, since after glycerine extraction with the hydrochloric acid, the resulting product is usually extreme dark with an offensive odor. Another extremely economical fat product which heretofore has had little commercial value is so called "yellow grease" from food processing wastes, which contains such a variety of vegetable and mineral fats that further treatment and separation of components is generally not feasible.
Although sulfur-chlorinated cyclic oils by themselves, as generally disclosed in the previous referenced application, have been found to exhibit not only good anti-weld properties, but some extreme pressure properties, greatly enhanced extreme pressure properties with improved wetting may be obtained by mixing these cyclic oils with sulfur-chlorinated fatty derivatives. However, in most instances, the addition of known and available sulfur-chlorinated fats greatly increases the cost of the previously economical sulfur-chlorinated cyclic oil. Sulfur-chlorinating less expensive fat products such as yellow grease or acidulated foots and then attempting to blend them with a cyclic oil is at best a risky business due to limited compatibility and storage life.